This invention relates to a urethral catheter, and to a method of delivering medication such as infectious vaccines, for example, bacillus Calmette-Guerin (BCG) vaccine, into the bladder for treating bladder cancer.
Urethral catheters are known for insertion through the urethra into the bladder for administering medication or radiopaque dyes into the bladder. Drawbacks of known urethral catheters include catheter traumatization of the urethral canal by the insertion and presence of the catheter in the urethra. In addition, inflammation and infection of the urethra can result from fluids passing from the catheter and into contact with the irritated urethra.
Previous attempts to prevent urethral infection include the indwelling urinary catheter disclosed in U.S. Pat. No. 4,579,554, in which deep grooves are provided along the length of the catheter for washing and cleansing the outside of the catheter so that the mucosa of the penile urethral canal is irrigated to reduce infection. Furthermore, a balloon is attached to the distal end of the catheter for being inflated when the catheter is in place in the bladder. The balloon both anchors the catheter and seats snugly against the wall of the bladder to resist escape of infected fluids into the sterilely treated urethra. This catheter is apparently designed chiefly for draining the bladder over a period of time, and has no mechanism for ensuring that a medication is not prematurely administered.
A catheter such as in the above-described U.S. Pat. No. 4,579,554 could not be safely used for administering BCG into the bladder of bladder cancer patients. BCG is highly toxic, and has been known to result in death when prematurely released within the urethra in the event of catheter traumatization. Given that the indwelling urinary catheter has a permanently open flow aperture at the distal end, leakage of BCG could occur through that opening while the catheter is being inserted through the urethra before the distal end is completely within the bladder, resulting in infection and, perhaps, death.